Some observables as an indication of atomic nuclear shape phase transition

A. Leviatan

Jin Zhang

Using interacting boson model, shape phase transitions from U(5) to O(6) and from U(5) to SU(3) are studied in the space of two control parameters. Some simple shape phase diagrams in terms of the order parameter and one of the control parameters are presented. Spectra and E2 transition rates are used to construct observables. It is shown that these observables exhibit the behavior of the shape phase transition, namely a peak structure at and after the critical point.

Pavel Cejnar, Jan Jolie, Richard F. Casten

Signatures of criticality in the evolution of the nuclear ground-state shapes across the $N\ifmmode\times\else\texttimes\fi{}Z$ plane are discussed. Attention is paid to specific data indicating sudden structural changes in various isotopic and isotonic chains of medium-mass and heavy even-even nuclei, as well as to diverse theoretical aspects of the models used to describe these changes. The interacting boson model and the geometric collective model, in particular, are discussed in detail, the former providing global predictions for the evolution of collective observables in nuclei between closed shells and the latter yielding a parameter-efficient description of nuclei at the critical points of shape transitions. Some issues related to the mechanism of first- and second-order quantum phase transitions in general many-body systems are also outlined.

Amir Jalili, H. Sabri

FRANCESCO IACHELLO

Elizabeth T. Williams, R. J. Casperson, Volker Werner

A study of first and second order nuclear shape phase transitional behavior in yrast states of even-even nuclei in the context of the Interacting Boson Model-1 is presented. Finite boson number effects are identified using calculations with up to 150 bosons, and the role of the rotational degree of freedom of observables in first and second order quantum phase transitional nuclei is discussed. We aim to provide a first investigation of the angular momentum dependence of experimentally accessible phase transitional signatures in finite-sized quantum nuclear systems.